The present invention relates to a package configuration of a semiconductor device which employs a tape in the mounting of a semiconductor chip, and to a liquid crystal module incorporating the semiconductor device.
A liquid crystal display device used as a personal computer monitor, and portable devices such as a terminal device of a mobile phone and a game utilize a tape for mounting a semiconductor chip called TAB (Tape Automated Bonding). In addition, in this mounting is adopted a package configuration such as a TCP (Tape Carrier Package) and a COF (Chip on Film). Note that, an example of the mounting of a semiconductor chip according to the TAB is disclosed in Japanese Unexamined Patent Publication No. 57233/1991 (Tokukaihei 3-57233 published on Mar. 12, 1991).
FIGS. 14 and 15 illustrate a conventional mounting method, of which FIG. 14 is a front view and FIG. 15 is a cross section of FIG. 14 taken along a cross sectional line Axe2x80x94A. FIGS. 14 and 15 show the TCP configuration. A tape 3 is formed by patterning a Cu wiring pattern 2 on a substrate 1 composed of an organic material such as polyimide. The Cu wiring pattern 2 has extending portions 2a and 2b which are extending from peripheral portions of the substrate 1 so as to be parallel to each other. Then, via an anisotropic conductive film and the like, the extending portions 2a and 2b are electrically connected to a pad of a liquid crystal panel and a pad of a power supply or a print board from which an image data signal is transmitted, respectively.
The substrate 1 includes device holes 6 and 7 corresponding to semiconductor chips 4 and 5 to be mounted. The Cu wiring pattern 2 is lead into these device holes 6 and 7 so as to be inner leads 2c. Portions of the Cu wiring pattern 2 such as the inner leads 2c and the extending portions 2a and 2b are given Sn plating (not shown). Corresponding to Au bumps 8 disposed on every side of semiconductor chips 4 and 5 each having a rectangular shape, the inner leads 2c project to the interior of the device holes 6 and 7 through the four sides of each rectangular hole. The Au bumps 8 of the semiconductor chips 4 an 5 are subject to eutectic bonding with the Sn which was applied to the inner leads 2c by electroless plating, that is called ILB (Inner Lead Bonding).
Periphery w including the device surfaces of the semiconductor chips 4 and 5, and the inner leads 2c thus mounted are sealed with a resin 9, thereby maintaining the mechanical strength while being protected from the surrounding environment. Note that, the tape 3 is protected by a covering of a solder resist 10, except for electrode portions thereof such as the inner leads 2c. The foregoing processes are sequentially performed while remaining on the tape 3, thereby efficiently performing mounting.
Meanwhile, electric devices have been given enhanced functions in recent years, which calls for multi-chip mounting on a single tape as discussed. In liquid crystal modules to be mounted on small devices, such as, for example, terminal devices of mobile phones and games, in order to realize efficient operations of a driver with respect to the increasing number of wires in a liquid crystal panel a memory is provided first in an IC of the driver. This results in an increase in memory capacity due to a further increase in the number of pixels and adopting of colors. For example, when manufacturing a common and segment driver and an SRAM according to a process (design rule) necessary for the common and segment driver, an SRAM portion occupies 60% of the whole area of a semiconductor chip.
On the other hand, though the driver portion that is required to be resistant to pressure in order to control contrast in pixels of a liquid crystal panel is not suitable for manufacture by minuscule processing, yet adopting a minuscule process in the memory portion enables the memory portion to accommodate to integration which corresponds to the number of wires in the liquid crystal panel. Therefore, it is feasible that the driver portion and the memory portion are formed by an optimum process (design rule), while mounting two semiconductor chips, a driver chip and an SRAM chip, on a single tape.
However, in the foregoing mounting configuration, the Au bumps 8 of the semiconductor chips 4 and 5 are disposed on the periphery of the semiconductor chips 4 and 5 having the rectangular shape, for the ILB. In correspondence with this, the inner leads 2c project to the interior of the device holes 6 and 7 through all the four sides of each rectangular hole, thereby accommodating to a high-density arrangement of the Cu wiring pattern 2. This raises a problem such that, of all the four sides of each of the device holes 6 and 7, through a side orthogonal to the extending portions 2a and 2b can be formed the straight Cu wiring pattern 2; however, with regard to a side parallel to the extending portions 2a and 2b, the routing of the Cu wiring pattern 2 becomes complicated, thereby resulting in a process defect in the tape 3 and an increase in the size of the tape 3 due to the necessity for routing space.
This kind of problem emerges when mounting the semiconductor chips 4 and 5 individually on the tape 3, and becomes more pronounced in the mounting of a plurality of semiconductor chips 4 and 5. Accordingly, multi-chip mounting cannot easily be realized due to the foregoing problems, though it has been called for.
It is an object of the present invention to provide a semiconductor device capable of compact mounting of a plurality of semiconductor chips on a single tape, and a liquid crystal module adopting the semiconductor device.
The semiconductor device of the present invention is made up of a tape having an organic substrate and a wiring pattern formed on the organic substrate, and a plurality of semiconductor chips mounted on the tape, where the semiconductor chips individually have a lengthwise rectangular shape, and the semiconductor chips having the lengthwise rectangular shape are mounted so as to have a long side substantially perpendicular to an extending direction of the wiring pattern.
With the foregoing arrangement, the semiconductor device having a TCP or COF configuration, including semiconductor chips mounted on a tape, is mounted in such a manner that each semiconductor chip having the lengthwise rectangular shape has bumps along its long side which is substantially perpendicular to the extending direction of the wiring pattern.
Accordingly, numerous wires of the wiring pattern can be provided so as to be substantially parallel to each other and substantially straight to a destination of in-/output. Particularly, when the semiconductor chips have no complicated routing therebetween, and the chips are connected in a substantially straight-line wiring pattern, an interval between the chips can be reduced. Accordingly, in the mounting of a plurality of semiconductor chips, devices to be connected can be reduced in size by reducing a width of the tape.
Further, the semiconductor device of the present invention has an arrangement in which the semiconductor chips have a difference in thickness.
With the foregoing arrangement, bonding is performed on a thinner semiconductor chip first, thereby reducing the risk of damage to the semiconductor chip as a result of contact with a bonding tool (bonder equipment).
Consequently, the semiconductor chips can be mounted in the vicinity, while reducing restriction on a mounting position of a chip, and allows a spacious design, for example, in the routing of the wiring pattern.
Furthermore, in the semiconductor device of the present invention, on the tape is formed a slit between the semiconductor chips, so as to ease bending of the tape.
With the foregoing arrangement, flexibility can be improved in composition such that the tape is bent with respect to a back side of a liquid crystal panel to be connected.
Further, the semiconductor of the present invention has an arrangement in which a wiring pattern between the semiconductor chips is free from a solder resist for ease of bending.
With the foregoing arrangement, since the solder resist is not formed over the wiring pattern between the semiconductor chips, it is less feasible that bending the tape at a portion free from the solder resist may result in a break in the wiring pattern, thereby improving flexibility in composition such that the tape is bent with respect to the back side of the liquid crystal panel to be connected.
Furthermore, the semiconductor device of the present invention has an arrangement in which the semiconductor chips are at least two chips selected from an SRAM, a liquid crystal driver IC and a controller-use IC.
With the foregoing arrangement, for example, more elements are required in comparison with a DRAM (dynamic RAM) and the like; however, the semiconductor device is made up of two chips one of which is the liquid crystal driver IC and the other is the SRAM (static RAM) suitable as a memory capable of low power consumption and being provided adjacent to the liquid crystal driver IC.
Alternatively, the semiconductor device may have three chips: the SRAM, the liquid crystal driver IC and the controller-use IC. Alternatively, the semiconductor device may have two of these chips arbitrary selected.
Further, the liquid crystal module of the present invention includes any one of the foregoing semiconductor devices that is connected to a liquid crystal panel.
Additional objects, features, and strengths of the present invention will be made clear by the description below. Further, the advantages of the present invention will be evident from the following explanation in reference to the drawings.